Field of the Invention
The present invention relates to an ophthalmologic apparatus exemplified by a fundus examination apparatus used to acquire a tomographic image of the fundus of an eye to be inspected, a control method thereof, a processing apparatus, and a processing method.
Description of the Related Art
In recent years, an apparatus using optical coherence tomography (OCT), which acquires a tomographic image by utilizing the interference of low-coherence light, has been in practical use (hereinafter referred to as the OCT apparatus in some cases). The OCT apparatus allows a tomographic image to be acquired at a resolution of approximately the wavelength of the light incident upon an object to be inspected, thus making it possible to acquire a tomographic image of an object to be inspected with a high resolution. The OCT apparatus is useful especially as an ophthalmologic apparatus for obtaining the tomographic image of the retina positioned on a fundus.
An examiner compares a tomographic image of a subject obtained by the OCT apparatus with a tomographic image of a normative eye or a tomographic image of the same subject acquired in the past thereby to use the result of the comparison as an aid in diagnosis. The comparison is frequently performed on, for example, the thickness of a functional layer (e.g. the thickness of a nerve fiber layer).
Japanese Patent Application Laid-Open No. 2009-89792 describes a technique in which position information for comparing the layer thicknesses of tomographic images is determined, the position information is stored in a normative eye image, a layer thickness corresponding to the position is extracted from an acquired tomographic image, and a difference from the layer thickness of the normative eye is calculated.